Search

Competing Interests: Luke MaeseHonoraria: Jazz PharmaceuticalsConsulting or Advisory Role: Jazz Pharmaceuticals Jennie VagherConsulting or Advisory Role: InVitae Samuel H. CheshierPatents, Royalties, Other Intellectual Property: International Patent Application No. PCT/US2018/020905 Entitled: Treatment of Pediatric Brain Tumors with Targeting of CD47 Pathway. First Named Inventor: Sharareh Gholamin, Your Ref.: S17-082, Our Ref.: STAN-1400WO; US Application Serial No. 15/912,447 Entitled: Treatment of Pediatric Brain Tumors with Targeting of CD47 Pathway. First Named Inventor: Sharareh Gholamin, Your Ref.: S17-082, Our Ref.: STAN-1400; International Patent Application No. PCT/US2018/020905 Entitled: Treatment of Pediatric Brain Tumors with Targeting of CD47 Pathway. First Named Inventor: Sharareh Gholamin, Your Ref.: S17-082, Our Ref.: STAN-1400WO; US Application Serial No. 15/912,447 Entitled: Treatment of Pediatric Brain Tumors with Targeting of CD47 Pathway. First Named Inventor: Sharareh Gholamin, Your Ref.: S17-082, Our Ref.: STAN-1400No other potential conflicts of interest were reported.

Brain tumors are the most common solid tumors of childhood, and the genetic drivers and optimal therapeutic strategies for many of the different subtypes remain unknown. Here, we identify that bithalamic gliomas harbor frequent mutations in the EGFR oncogene, only rare histone H3 mutation (in contrast to their unilateral counterparts), and a distinct genome-wide DNA methylation profile compared to all other glioma subtypes studied to date. These EGFR mutations are either small in-frame insertions within exon 20 (intracellular tyrosine kinase domain) or missense mutations within exon 7 (extracellular ligand-binding domain) that occur in the absence of accompanying gene amplification. We find these EGFR mutations are oncogenic in primary astrocyte models and confer sensitivity to specific tyrosine kinase inhibitors dependent on location within the kinase domain or extracellular domain. We initiated treatment with targeted kinase inhibitors in four children whose tumors harbor EGFR mutations with encouraging results. This study identifies a promising genomically-tailored therapeutic strategy for bithalamic gliomas, a lethal and genetically distinct brain tumor of childhood.

Myxopapillary ependymoma (MPE) is a rare subtype of ependymoma in children. Though classified as a Grade I tumor, their unpredictable behavior and propensity for local and disseminated recurrence poses a therapeutic challenge. Till date no predictive molecular markers exist for such recurrence, especially with dissemination. We demonstrated that Epidermal Growth Factor Receptor (EGFR) expression was seen in relapsed MPE both at diagnosis and at recurrence and none in the nonrecurring tumors. This finding suggests EGFR could be a predictive biomarker for recurrence in MPE., (Copyright © 2011 Wiley Periodicals, Inc.)

Oligodendroglioma is an uncommon childhood tumor and is more chemosensitive than other malignant glial neoplasms. Treatment involves gross total resection, and if anaplastic, radiation and chemotherapy. Distinct genetic alterations are associated with improved prognosis. We report a child with a low-grade oligodendroglioma that recurred as a high-grade oligodendroglioma and ultimately as extraneural systemic relapse. It was initially responsive to temozolomide, cyclophosphamide, etoposide, and carboplatin, perhaps predicted by combined loss of heterozygosity at 1p and 19q. This chemotherapy may be promising in treating malignant oligodendroglioma. However, he succumbed to progressive systemic disease. Positron emission spectroscopy scan was useful in sequentially assessing his disease.

Background: Amplification of the N-myc oncogene is associated with adverse outcomes in the common childhood tumor, neuroblastoma. Because the transforming properties of Myc are related to its ability to modulate gene expression, the authors used cDNA microarrays to identify potential Myc target genes., Methods: Expression levels of 4608 genes were analyzed in a series of neuroblastoma cell lines. Identical analyses were performed in a panel of medulloblastoma cell lines to identify c-Myc targets and to determine the extent to which N-Myc targets and c-Myc targets were shared. Comparisons were made between cell lines with high levels versus low levels of Myc protein expression., Results: Array analyses yielded 121 genes with increased expression levels (>or= 1.65-fold) and 9 genes with decreased expression levels in N-Myc-expressing versus nonexpressing cell lines. Many of these were newly identified targets of biologic interest. Fifty percent of the N-Myc targets (60 of 121) were mutual c-Myc targets. A significant correlation between the level of N-myc and selected target gene expression was demonstrated independently in 27 neuroblastoma tumor samples and in an N-myc-inducible cell line system., Conclusions: A number of diverse pathways are modulated by N-Myc in neuroblastoma. Although, overall, there was significant correlation between myc and target transcript expression among cohorts of tumors, great variability in levels of target expression was seen among individual tumor samples, and this biologic heterogeneity in the levels of target gene expression may offer insight into differences in the clinical behavior of neuroblastoma and may prove to be of prognostic significance in the future., (Copyright 2003 American Cancer Society.DOI 10.1002/cncr.11584)

Apoptosis is the primary mechanism through which most chemotherapeutic agents induce tumor cell death. The purpose of this study was to determine the extent to which blasts from children with leukemia undergo a uniform apoptotic death pathway in vivo. The expression of pro- and anti-apoptotic proteins p53, p21, MDM-2, BCL-2, BCL-X(L), BCL-X(S), and BAX, and caspase-3 activity was determined in circulating blasts collected from the peripheral blood of children with leukemia prior to, and at serial time points following chemotherapy. Culturing blasts ex vivo for 12 h assessed spontaneous apoptosis and the increment induced by chemotherapy. Baseline apoptosis varied between 3% and 29%. Twenty-four hours following chemotherapy the increase in the percentage of cells undergoing apoptosis ranged from <1% to 38%. Eleven of 20 patients who received initial treatment with a p53-dependent drug showed an increase in p53 expression. In these patients, the levels of p53 target genes were also increased. A uniform pattern of BCL-2 family protein expression was not observed and only a minority of samples showed a change that would favor apoptosis. We conclude that that the initial apoptotic response to chemotherapy in children with leukemia is variable involving both p53-dependent and p53-independent pathways.

Purpose: Medulloepithelioma is an embryonal multipotential neuroepithelial tumor with a striking potential for divergent differentiation. It is usually intraocular or intracerebral and associated with a good prognosis only if completely surgically excised. Data regarding therapy in children with incompletely resected tumors are limited., Patient and Methods: A girl was born with a large, peripheral, congenital medulloepithelioma associated with complete absence of the left hindquarter and anus. Plain film, ultrasonography, and magnetic resonance imaging demonstrated complete absence of the left kidney and hemipelvis. A subtotal resection of the mass and reconstruction of the tumor-related anatomical defects were performed., Results: Pathologic examination showed neuroglia and pseudostratified neuroectoderm diagnostic of medulloepithelioma. She was treated with multiagent chemotherapy including vincristine, cisplatin, cyclophosphamide, carboplatin, and etoposide. She is now 50 months of age and developing normally without recurrent disease., Conclusions: A child with an incompletely resected congenital peripheral medulloepithelioma who has experienced long-term disease-free survival after treatment with chemotherapy is described. This report supports a role for adjuvant chemotherapy in the treatment of children with peripheral medulloepithelioma.

Purpose: Apoptosis plays a crucial role in normal development and mediates tumor response to chemotherapy. This study investigated the pattern of apoptotic gene expression in brain tumor tissue specimens and cell lines., Materials and Methods: BCL2, BCLXL, BCLXS, and BAX transcripts were amplified using reverse transcriptase polymerase chain reaction in 7 high-grade gliomas (HGGs), 7 ependymomas, and 6 cell lines (2 glioblastomas, 3 medulloblastomas, and 1 supratentorial-primitive neuroectodermal tumor [PNET]). Immunohistochemical staining for BCL2, BCLX, BAX, and p53 was performed in 7 pediatric low-grade gliomas (LGGs) and 7 pediatric HGGs., Results: Six of seven gliomas, all ependymomas, and all glioblastoma and medulloblastoma cell lines expressed BCLXL and BAX. BCL2 expression was only detected in the supratentorial PNET line PFSK. BCLXS was absent in all tumors. By immunohistochemistry, no glial tumors stained positively for BCL2. Similar BAX and BCLX protein expression was observed in LGG and HGG. Three of five glioblastomas showed significant p53 expression., Conclusions: Coexpression of proapoptotic and antiapoptotic genes in human brain tumors supports the hypothesis that the relative expression of competing genes determines apoptotic threshold.

In this study, the authors sought to investigate the response rate and toxicity of carboplatin in patients with progressive low-grade glioma (LGG). Thirty-two patients with progressive LGG were treated with carboplatin at a dosage of 560 mg/m(2). Treatment was given at 4-week intervals and continued until the disease progressed, unacceptable toxicity supervened, or for 12 additional courses after achieving maximal response. Patients with stable disease were treated with a total of 12 cycles. All patients were treated as outpatients. Patients were evaluated for response to treatment and toxicity. All patients received a minimum of two cycles of carboplatin, and were examined for response. A partial response was achieved in nine patients (28%) and a minimal response in two (6%), for an overall response rate of 34% (11 of 32 patients). Eighteen patients (56%) had stable disease. A partial response was achieved in the nine patients after a median of six cycles (range 4-11 cycles), a minimal response was achieved in the two patients after five cycles. Glioma progression was noted in three patients after three, five, and five cycles, respectively. The 11 patients in whom some response was achieved had either an optic pathway tumor or a juvenile pilocytic astrocytoma. Twenty-six of the 32 patients had those characteristics, making the response rate in that group 42% (11 of 26 patients). Thirty-two patients received a total of 387 cycles of chemotherapy. Hematological toxicity was moderate. Twenty-one patients developed thrombocytopenia (platelet count < 50,000/microl); three patients required one platelet transfusion each. Nine patients developed neutropenia (absolute neutrophil count < 500/microl); one developed fever and required administration of antibiotic agents. One dose adjustment in each of the patients prevented further thrombocytopenia and neutropenia. Two patients with stable disease died of respiratory complications. One patient developed Grade III ototoxicity after receiving five cycles, one patient developed hypersensitivity to carboplatin, and none developed nephrotoxicity. Carboplatin given at a dosage of 560 mg/m(2) every 4 weeks has activity in patients with progressive LGG. This drug regimen is relatively simple and well tolerated. Further investigation and longer follow-up study are warranted.

Purpose: Advanced stage neuroblastoma (NB) is generally associated with a grim prognosis. Surveillance radiographic imaging is usually performed frequently to detect progressive (PD) or recurrent disease (RD) and promptly begin salvage therapy. We studied children with advanced stage NB to determine both how PD or RD was detected and the impact of detection in asymptomatic versus symptomatic children on outcome., Study Design: A retrospective review of children with NB was performed between 1984 and 1996. Children with advanced stage NB and RD or PD were further studied., Results: Thirty-two children with advanced stage NB and PD or RD were identified. The median time to PD or RD after diagnosis was 1 year 2 months. Nine (28%) children progressed on therapy. One child underwent confirmatory biopsy of residual scan abnormalities at the completion of planned therapy. Disease recurred in 22 (67%) children after therapy (median time 6 months). Two children (6%) had RD detected by surveillance studies associated only with elevated urinary catecholamines. Despite recent normal studies, 29 of 32 children (91%) had onset of new symptoms prompting confirmatory radiographic studies., Conclusions: Surveillance radiographic imaging was insensitive in detecting PD or RD in children with advanced stage NB. Careful history, examination, and selective laboratory evaluation were sensitive and cost-effective in detecting PD or RD.

Purpose: Malignant ectomesenchymomas are tumors that exhibit both mesenchymal and neuroectodermal elements (1). We report a case thought to represent a malignant ectomesenchymoma arising in the kidney with cytogenetic abnormalities that may provide insight into the biologic basis for this unusual tumor., Methods: We discuss the clinical features, histopathologic findings, cytogenetics, treatment, and outcome of a child with a malignant ectomesenchymoma arising in the kidney., Results: An asymptomatic 16-month-old boy had a large abdominal mass. The resected tumor contained sheets of spindled cells that expressed mesenchymal markers and cartilaginous differentiation, interspersed with clusters of ganglion cells that expressed neural markers. No blastemal or epithelial elements were demonstrated. Cytogenetic analysis of the tumor revealed a hyperdiploid count with multiple numerical and structural abnormalities, including a translocation between chromosomes 12 and 15. In addition to the surgical resection, the patient was successfully treated with adjuvant chemotherapy and local radiation therapy., Conclusion: This is the first report of which we are aware of an ectomesenchymoma arising within the kidney. A subset of malignant ectomesenchymomas may be related to the Ewing's family of tumors (EFTs) (2), but this case did not exhibit cytogenetic features consistent with EFT. Thus, the malignant ectomesenchymoma phenotype probably represents a heterogeneous group of tumors with different genotypes and origins. Cytogenetic analysis may be instrumental in determining the appropriate therapeutic approach when faced with such a neoplasm. The outcomes of 12 other children with ectomesenchymoma are reviewed.

Purpose: The purpose of this study was to determine the incidence of c-Myc protein expression in medulloblastoma/primitive neuroectodermal tumor (MB/PNET) and to identify mechanisms in addition to c-myc gene amplification that lead to increased protein expression., Methods: We analyzed c-myc gene copy number, mRNA level and protein expression in a panel of MB/PNET cell lines. C-Myc protein levels were assessed in tumor specimens and cell lines using immunohistochemical staining with a c-Myc-specific monoclonal antibody., Results: Southern analysis confirmed c-myc gene amplification in the D425 MED cell line and re-arrangement of one allele in D283 MED, which was analyzed further and appeared to represent a small deletion 3' of exon 3. C-myc transcript levels were dramatically elevated in both lines. Using a c-myc probe, fluorescence in situ hybridization (FISH) showed c-myc present in 3 tandem copies at 8q24 in D283 MED and multiple copies as double minutes in D425 MED. Immunohistochemistry showed c-Myc protein expression in 9 of 10 tumors and all cell lines, regardless of gene amplification status or level of mRNA expression., Conclusions: c-Myc protein expression is common in MB/PNET tumor specimens and cell lines. Elevated protein levels are observed in the absence of amplification, suggesting that multiple mechanisms of c-myc dysregulation may be involved in MB/PNET. These studies support a role for c-Myc in the development of this common childhood tumor.

Few studies have analyzed the relationship among pathology, therapy-induced changes, proliferative activity, and outcome for rhabdomyosarcoma (RMS), despite the challenges of histopathologic interpretation of this tumor after treatment. Although cytodifferentiation and decreased mitotic activity after treatment were documented previously, the clinical consequences of these changes are uncertain because of the small number of cases analyzed. We analyzed 16 RMSs with pre- and post-treatment specimens for clinicopathologic features, outcome, and immunohistochemical data on formalin-fixed, paraffin-embedded tissue for vimentin, smooth muscle actin, muscle-specific actin, desmin, myoglobin, p53 protein, topoisomerase II-alpha, and MIB-1 proliferative activity. Four of eight alveolar (ARMS), five of five botryoid (BRMS), and two of three nonbotryoid embryonal (ERMS) RMSs displayed varying degrees of post-therapeutic histologic maturation and expressed one or more myoid markers. The remaining five RMSs had no cytodifferentiation. Myoid marker expression did not change significantly. In BRMS, MIB-1 and topoisomerase II-alpha proliferative activity decreased after therapy and correlated with cytodifferentiation and survival. This relationship was less clear for ERMS and ARMS. Five nonbotryoid RMSs without cytodifferentiation had either unchanged or increased proliferative activity, and four of these patients died of RMS. Six nonbotryoid RMSs with both cytodifferentiation and residual foci of undifferentiated cells had variable outcomes, including longer survival. We conclude that BRMS and ERMS exhibit therapy-induced cytodifferentiation more frequently than does ARMS. Cytodifferentiation and decreased proliferative activity are associated with favorable outcome in BRMS; unchanged or increased post-therapeutic proliferative activity suggests aggressive biologic potential in ERMS and ARMS. Combined patterns of cytodifferentiation and residual undifferentiated foci might be associated with increased, decreased, or unchanged proliferative activity and are difficult to interpret, but the presence of cytodifferentiation might presage an improved survival. Immunohistochemical analysis for proliferation markers might be useful for highlighting foci of less differentiated RMS or cytodifferentiated tumor cells in contrast to non-neoplastic, terminally differentiated muscle cells.

Ifosfamide, a nitrogen mustard derived alkylating agent commonly used in the treatment of solid tumors, has been associated with neurotoxicity in 5-33% of treated patients. Encephalopathy most often occurs during or shortly following drug administration, with increased drowsiness or irritability, confusion, hallucinations, visual blurring, extrapyramidal dysfunction, cranial nerve abnormalities, incontinence, generalized muscle twitching, seizures, and coma reported in infants, children, and older adults. While most reported neurologic abnormalities associated with ifosfamide have been reversible, encephalopathy resulting in death has occurred. We now report an infant who developed ifosfamide-induced encephalopathy, loss of developmental milestones, progressive brain atrophy, and cessation of cranial growth. This is the first case of cerebral atrophy and loss of developmental milestones that has been reported in a pediatric patient treated with ifosfamide. Given the efficacy of this anti-neoplastic agent and its increasing use in pediatrics, further investigation is indicated, especially in infants where brain growth is ongoing.

Purpose: Hyperleukocytosis secondary to acute leukemia is a medical emergency. Intracranial hemorrhage often leads to death in this setting. Early efforts to prevent this serious complication have included emergent cranial irradiation, with its associated morbidity when used in the young child. Currently, exchange transfusion and/or leukapheresis are employed to acutely lower the peripheral leukocyte count., Patients and Methods: We report three infants with acute leukemia and hyperleukocytosis in whom intravenous hydration, alkalinization, and allopurinol therapy alone produced rapid and dramatic decreases in the peripheral leukocyte count., Results: The maximal decrease in leukocyte count averaged 88% within 70 h of starting conservative management. A fall in leukocyte count to < 100 x 10(9)/L was noted at an average of 15 h following hospitalization. No patient developed complications., Conclusions: When comparing this approach to exchange transfusion and leukapheresis we find it to be both safe and effective. Children with hyperleukocytosis in association with acute lymphocytic leukemia who present without life-threatening complications of an extremely high leukocyte count can be safely and effectively managed with intravenous hydration, alkalinization, and allopurinol therapy.

Profound clinical deficits may be associated with insults to the brainstem, making management of patients with brainstem gliomas very complex. Small changes in the radiographic appearance of a brainstem tumor may be associated with significant clinical deterioration. Furthermore, both magnetic resonance imaging and computed tomography are frequently unable to differentiate between therapy-related tissue reactions and progressive tumor. Two clinical scenarios particularly difficult to resolve include: (1) transient radiographic and clinical deterioration following hyperfractionated radiotherapy, and (2) clinical deterioration in a patient who has failed initial therapy, but has stable radiographic findings following a second therapy. We report a child with a pontine glioma whose tumor progression was demonstrated more convincingly with a 18F-deoxyglucose positron emission scan than with magnetic resonance imaging. PET scans may be helpful in confirming that tumor progression is responsible for clinical deterioration in a patient whose MRI scans remain stable.

A 19-month-old girl with idiopathic severe aplastic anemia refractory to multi-agent immunosuppressive therapy developed severe platelet alloimmunization following several months of platelet transfusions. She became refractory to human leukocyte antigen (HLA)-matched platelet transfusions and experienced frequent episodes of bleeding. She was treated with intravenous vincristine administered weekly for three doses and showed marked improvement in both clinical and laboratory response to platelet transfusions. When vincristine was held for 3 weeks, she again became refractory to HLA-matched platelet transfusion. Reinstitution of vincristine resulted in cessation of clinical bleeding and improved response to platelet transfusion. The mechanism of response likely involves selective delivery of cytotoxic drug to macrophages. To our knowledge this is the first reported case of alloimmune thrombocytopenia responsive to vincristine.

We treated three children with optic pathway gliomas who had progressive disease associated with metastatic spread to the leptomeninges. One patient had radiographic resolution of leptomeningeal disease after treatment with intravenous carmustine and oral mercaptopurine but died of progressive pulmonary fibrosis. The second patient was treated with intravenous thiotepa, and the leptomeningeal disease remained stable. The third patient was treated with intravenous vincristine sulfate, cyclophosphamide, cisplatin, and etoposide and had a significant size reduction of the leptomeningeal lesion. Although leptomeningeal dissemination is a seemingly rare event, it is important that all children with optic pathway gliomas be considered for this possibility, particularly after the onset of new, atypical neurologic symptoms.